Applied Radia ion and Iso opes 64 (2006) 502–507
O e coming ICP-QMS ins umen al limi a ions o
99
Tc de e mina ion
in en i onmen al solid samples using adiochemis y
Jose
´Luis Mas
a,
, M. Ga cı´a-Leo
´n
b
, J.P. Bolı´ a
c
a
Depa amen o de Fı
´sica Aplicada I, Uni e sidad de Se illa, Escuela Uni e si a ia Poli e
´cnica, C/Vi gen de A ica, 7, 41012 Se ille, Spain
b
Depa amen o de Fı
´sica A o
´mica, Molecula y Nuclea , Uni e si y o Se illa , Apdo. 1065, 41080 Se illa, Spain
c
Depa amen o de Fisica Aplicada, Uni e sidad de Huel a, Facul ad de Ciencias, Campus del Ca men, 21071-Huel a, Spain
Recei ed 21 Sep embe 2005; accep ed 13 No embe 2005
Abs ac
Besides i s capabili ies, quad upole-based ICP-MS coun ing es ablishes se e al limi a ions on
99
Tc analysis in en i onmen al samples.
O e coming hese limi a ions equi es he use o adiochemical me hods. We ha e de eloped a new me hod o he de ec ion o
99
Tc by
ICP-QMS in solid en i onmen al samples. In o de o imp o e he limi o de ec ion o he echnique, high amoun s o solid samples
(X100 g) a e used. Hence, g ea amoun s o he in e e ing elemen s a e in ol ed in he p ocess, and he e o e special emphasis is pu on
achie ing a good commi men be ween adequa e ma ix elemen s emo al and a minimiza ion o he limi o de ec ion. The pe o mances
o he me hod a e analyzed in e ms o con enien ly defined figu es o me i . The de eloped me hod is applied o se e al allou le el
samples. In his way, he eal pe o mances and especially he eal limi a ions o his me hod a e shown.
Keywo ds: Techne ium; ICP-MS; Concen a ion ac o ; Decon amina ion ac o
1. In oduc ion
99
Tc (T
1/2
¼2.11 10
5
yea s) is a low ene gy b-emi e
a ising om he fission o
235
Uo
239
Pu a a ela i ely
high a e (6%). I s en i onmen al ele ance is well
es ablished. Howe e , i s de e mina ion in non-pe u bed
si es is di ficul due o he sub-pp le el concen a ions
in en i onmen al samples (Eh ha d and A ep, 1978;
Ga cı´a-Leo
´n e al., 1984).
ICP-MS is becoming a powe ul ool o he analysis o
99
Tc (Mo i a e al., 1991;Tagami and Uchida, 1993;
Nicholson e al., 1993). No sys ema ic di e ences we e
ound in a ecen in e labo a o y s udy, when he esul s
achie ed by ICP-MS we e compa ed o hose o he s
p oduced by adiome ic coun ing (McCa ney e al.,
1999a). A wide a ie y o adiochemical me hods ha e
been de eloped o he measu emen s o
99
Tc in all so o
en i onmen samples (E oglu e al., 1998;Kei h-Roach
e al., 2002;Go
´mez e al., 2001;McCa ney e al., 1999b).
Some o hem a e designed as ou ine me hods: he limi s
o de ec ion o he de eloped echniques a e in ag eemen
wi h he law egula ions. The adiochemical wo k is
minimized as much as possible dealing wi h small amoun
o samples (Nicholson e al., 1993;E oglu e al., 1998;
Go
´mez e al., 2001;Rameba
¨ck e al., 1998).
Howe e , we a e in e es ed in epea ing ou p e ious
99
Tc de ec ion capabili ies achie ed using gas flow coun ing
(Ga cı´a-Leo
´n e al., 1984;Sa
´nchez-Angulo and Ga cı´a-
Leo
´n, 1988;Ga cia-Leon e al., 1993). To do ha , he
ICP-MS echnique is p oposed. Tha should imply a
p econcen a ion o
99
Tc. Un o una ely, his echnique is
qui e mo e sensi i e o he sample ma ix e ec s han gas
flow de ec ion (see below) o Liquid Scin illa ion Coun ing
and, u he mo e, dealing wi h a high amoun o sample
usually causes he lowe ing o chemical eco e ies (e.g.,
Nicholson e al., 1993, limi ed he analyzed sample mass o
50 g when sedimen samples we e ea ed).
Special a en ion has been paid in he li e a u e o he
decon amina ion om Ru a oms due o he isoba ic
o e lap om
99
Ru (12.6% na u al abundance). Howe e ,
o many au ho s i seems ha he p oblem associa ed o he
0969-8043/$ - see on ma e doi:10.1016/j.ap adiso.2005.11.005

Co esponding au ho . Tel.: +34 959019782; ax: +34 954554341.
E-mail add ess: [email p o ec ed] (J.L. Mas).
p esence o Mo in he analyzed solu ion is no so se ious.
On he con a y, we ound unde ou wo king condi ions
ha aspi a ing solu ions wi h Mo concen a ions in he
ange o 10 ng g
1
(o highe ) would in oduce se e e
inc eases in he ins umen al esponse o mass 99. This
ac is due o he abundance sensi i i y (50 10
6
)
calcula ed o he middle ange o masses. On he con a y,
he in e e ences om
98
Mo hyd ides seem o be less
impo an unde ou wo king condi ions. The e ec o
o he in e e ences has been p e iously s udied (E oglu e
al., 1998;Mas e al., 2002). The e, hei negligible e ec on
he mass spec um has been shown.
In his pape , we p esen a obus adiochemical me hod
designed o he de ec ion o
99
Tc by ICP-MS. This me hod
is es ed wi h eal soil samples in o de o show hei
pe o mances and limi a ions acco ding o se e al figu es
o me i . Fi s , he concen a ion ac o (CF) o Tc is
defined as
CF ¼M0
M
RQ,
whe e M
0
is he sample mass submi ed o chemical
analysis, M
he mass o he final 2–5% HNO
3
acid
solu ion, which is aspi a ed by he ICP-MS, and R
Q
is he
chemical eco e y o Tc. Hence, his coe ficien ep esen s
he a io o he Tc concen a ion in he solu ion aspi a ed
by he ICP-MS o ha concen a ion in he s a ing
sample, be o e any chemical analysis. The desi ed me hod
should ha e a CF as high as possible. The in e se o he
CF, when e e ed o he in e e ing elemen s, has been
used in his wo k as decon amina ion ac o (DF); hence, i
should be also as high as possible. Finally, he minimum
de ec able mass concen a ion (MDMC) o ICP-MS was
also used o e alua e he p oposed me hods when hey we e
applied o eal samples. I is defined as
MDMC ¼
LOD
bCF ,
whe e b(coun s pp
1
) is he slope o he calib a ion cu e
o ou sys em a he ypical wo king condi ions, while LOD
is he Limi o De ec ion exp essed in e ms o he achie ed
coun ing a e. A comple e discussion on he dependence o
MDMC on he di e en a iables o he expe imen
(including he p esence o in e e ing iso opes) was
published elsewhe e (Mas e al., 2000).
2. Expe imen al
2.1. Ins umen a ion and samples
The quad upole ICP-MS Agilen 4500 wi h a Babing on
ype nebulize was used o he p esen ed expe imen s. The
ope a ing condi ions a e summa ized in Table 1.
The yield ace ,
99m
Tc, was ob ained om medical
gene a o s. I s con ibu ion o MDMC a ising om he
99m
Tc decay o
99
Tc is negligible, once p o ided ha some
gi en condi ions a e ollowed du ing he elu ion p ocess
(Mas e al., 2000). The ace was de e mined by measu ing
he in ensi y o i s 140.5 keV g-emission using a NaI(Tl)
scin illa ion coun e . Mo and Ru concen a ions we e
analyzed using he co esponding MERCK VI Ce i-P ep
mul i-elemen s anda d solu ion and an ALPHA APS-
100046-2 Ru s anda d solu ion, espec i ely.
99
Tc calib a-
ions we e pe o med using successi e dilu ions o an
99
Tc DAMRI s anda d solu ion (Gi -su -Y e e, Cedex,
F ance).
Di e en es s we e pe o med o op imise and de elop
he me hod he e p oposed by using unspiked eal soil
samples, which we e p e iously analyzed o o he adio-
nuclides (Mas e al., 2001). We conside ha his app oach
could be much mo e ealis ic han using s anda d
solu ions. The samples we e aken in he Sou hwes o
Spain. This a ea is only a ec ed by a mosphe ic allou , a
a e y low le el bea ing in mind he e y low la i ude. The
samples ha e a e y low o ganic ma e con en and he
le els o
137
Cs a e also e y low (o0.7 Bq kg
1
). The e o e,
we can es ima e
99
Tc concen a ions in he ange o
0.07 mBq kg
1
. Ou aim o limi o de ec ion is no so
ambi ious. The e o e, his should be a good sample ma ix
o he ealiza ion o ou expe imen s, once p o ided ha
hei concen a ions o Mo (in he ange o 1–2 ppm) and
Ru (up o 1 ppb) assu e he possibili y o using hem o
check he DF.
The me hod was alida ed analyzing he seaweed
samples used in he p e iously men ioned in e compa ison
exe cise o
99
Tc (McCa ney e al., 1999a). D . Vale ie
Oli e (Sco ish Uni e si ies Resea ch and Reac o Cen e)
kindly p o ided us wi h he samples.
Finally, se e al samples om he SW o Spain we e
analyzed in o de o es he me hod. The so-called DFS
sample co esponds o d y allou . I was aken a he
oo o he Facul y o Physics o he Uni e si y o
Se ille and co esponds o a d y pe iod om Ap il o
June 2001. Samples ZM1 and 2 co espond o ma ine
sea-g ass Zos e a Ma ina, which we e aken om he
coas o Huel a (Sou h–Wes o Spain) in Ma ch 2001.
Finally, samples 1SD1 and 1SD4, and 2S1 and 2S2
co espond o o es soil samples collec ed om a
Eucalyp us plan a ion also in he p o ince o Huel a in
1997 (Vaca e al., 2001).
ARTICLE IN PRESS
Table 1
Ope a ing condi ions o he ICP-MS ins umen
Radio equency powe (W) 1240
Sampling dep h (mm) 6.3
Ca ie gas (l min
1
) 1.17
Ex ac ion lens 1 (V) 150
Einzel lens No 2 (V) 5.5
Bias Omega lens (V) 41
Omega minus lens (V) 3
Quad upole ocus (V) 6
J.L. Mas e al. / Applied Radia ion and Iso opes 64 (2006) 502–507 503
2.2. Radiochemical me hod
2.2.1. P e ea men
To a po celain beake , 100–125 g pe sample eplica e a e
ans e ed and 150 ml o a 5% NH
4
OH solu ion a e
pou ed inside. The ace is added and mechanically
homogenized while his mix is so ly wa med un il he
e apo a ion o ha solu ion. The ea e he sample is
educed o ashes a 450 1C o 90 min. Techne ium is
dissol ed om he ashes using 8 M HNO
3
in he p esence
o 30% H
2
O
2
while wa ming on a ho pla e a 90 1C unde
eflux. In his way, we expec ha Tc appea s in he TcO
4

ion o m. The solu ion is fil e ed h ough a Wha man
CF/G glass fib e fil e . The p ecipi a e is leached again, and
hen he supe na an s a e mixed in o a 1 l p ecipi a e glass.
Hence, Tc emains dissol ed in a olume o app oxima ely
100–250 ml 8 M HNO
3
.
2.2.2. Concen a ion
A e ha , Tc is educed and p ecipi a ed ollowing a
p ocess widely used o wa e samples (Ga cı´a-Leo
´n e al.,
1984, 1993;Sa
´nchez-Angulo and Ga cı´a-Leo
´n, 1988). In
his case, we p opose his echnique o solid samples. The
solu ion pH is u ned o 3–4 by using 5% NH
4
OH. A
sui able mass o FeSO
4
7H
2
O (see Sec ion 3 o de ails) is
added in o de o educe he Tc o he +IV alence s a e. A
ce ain mass o FeCl
3
is also added as a p ecipi a ion
ca ie . The ea e , he solu ion is adjus ed o pH 9 using
NH
4
OH, and he cop ecipi a ion o Tc occu s.
This p ecipi a e is dissol ed wi h 3 M H
2
SO
4
(Nicholson
e al., 1993;Sa
´nchez-Angulo and Ga cı´a-Leo
´n, 1988;
Ga cia-Leon e al., 1993). Then Tc is ex ac ed in o
40–70 ml o TBP, which was p e iously condi ioned wi h
he same olume o 3 M H
2
SO
4
. Finally, he echne ium is
back-ex ac ed in o 25–30 ml o 25% NH
4
OH, in he
p esence o Xylene. In his way, he Tc is concen a ed as
he final olume dec eases, and a ce ain ac ion o Ru is
emo ed om he sample.
This solu ion is no sui able o be di ec ly analyzed by
ICP-MS. Thus, ha basic solu ion is gen ly e apo a ed
o almos d yness. We ha e no ound losses o Tc
du ing he e apo a ion om such a basic solu ion.
Then he esidue is dissol ed wi h 0.5 M HNO
3
and he
solu ion is adjus ed o 2–5% HNO
3
. This solu ion would
be eady o ou ICP-MS sys em. Howe e , many Mo
a oms would be p esen in his solu ion acco ding o
ou expe imen s. Hence, u he sample pu ifica ion is
pe emp o y.
2.2.3. Pu i ica ion
An Eich om’s TEVA Spec
TM
ch oma og aphic esin
mic o-column is used ollowing he sol en ex ac ion s ep.
Ve y high capaci y ac o s o Tc and Re ha e been
al eady epo ed (Tagami and Uchida, 2000). As we will
show below, hei pe o mances a e also qui e help ul o
emo ing he Mo a oms.
The 0.5 M HNO
3
p e iously p oduced is di ec ly loaded
on o such a mic o-column, which was p e iously condi-
ioned using fi s 5 ml o 8 M HNO
3
and hen 5 ml o a
0.5 M HNO
3
blank solu ion. The mic o-column is washed
using abou 40 ml o 2 M HNO
3
o emo e a ac ion o
he in e e ing elemen s (Mo and Ru). Finally, he Tc is
s ipped using a small olume (app oxima ely 10 ml) o 8 M
HNO
3
. Ru is almos o ally emo ed om he solu ion
wi h a single p ocess o loading, washing and s ipping
wi h his mic o-column (Mas e al., 2004). Howe e , he
p ocess mus o be epea ed in o de o imp o e he Mo
decon amina ion. This can be done using he same mic o-
column, wi hou ema kable losses on Tc e en ion. This
app oach has he ad an age o educing ea men cos s
wi hou a ec ing he adiochemical quali y o he analysis.
The e-loading p ocess has o be ca ied ou as ollows:
once he s ipping is done, he d ain is e apo a ed a low
empe a u e and he esidue is eco e ed wi h 0.5 M HNO
3
.
This app oach is less ime-consuming han dilu ing he fi s
s ipping solu ion, as he flow a e h ough he column is
small. This scheme could be epea ed wo o h ee imes
depending on he ini ial sample mass. Then he las elu ed
solu ion is e apo a ed again o nea d yness and eco e ed
wi h 2% HNO
3
. Finally, eco e y calcula ion and a om
coun ing a e ca ied ou .
3. Resul s and discussion
3.1. P e ea men pe o mances
In o de o check he losses o Tc a e he educ ion o
ashes, we de eloped a fi s es . A 150 g aliquo o e e y
sample ( es soils A, B,y, G) was spiked wi h he ace
and educed o ashes as desc ibed abo e. As we show in
Fig. 1, his p e- ea men does no p oduce any loss o Tc,
since he e en ion is always a ound 100%, being he mass
loss in o he same ange al eady de e mined in p e ious
wo ks (Mas e al., 2001).
An expe imen was ca ied ou o find he adequa e mass
o he educing agen . Se e al aliquo s o soil ashes,
unspiked wi h he ace , we e fil e ed as desc ibed abo e,
ollowing he p e ea men . Each fil a e was spiked wi h
he ace in he
99m
TcO
4

o m. Di e en amoun s o
educing agen we e used and he p ecipi a ion s ep was
ca ied ou . The supe na an was eco e ed by cen i uga-
ion, and he p ecipi a ion deg ee was measu ed in each
solu ion (Fig. 2).
Tc ac ion emaining in he solu ion apidly alls down
when he educing agen mass is g ea e han 0.05 g pe
g am o solid sample. As a esul i was ound ha some
15 g o educing agen pe li e o acid solu ion was
su ficien o ge a quan i a i e educ ion and an e ec i e
p ecipi a ion o Tc. Tha is qui e di e en om he amoun
o 7 g l
1
ound o ainwa e samples (Sa
´nchez-Angulo
and Ga cı´a-Leo
´n, 1988). Bu his is no s ange, howe e ,
due o he di e ences o he s udied ma ix: he leaching
solu ion con ains many mo e ma ix elemen s in compe i-
ARTICLE IN PRESS
J.L. Mas e al. / Applied Radia ion and Iso opes 64 (2006) 502–507504
ion wi h Tc o he educing compound han a ainwa e
sample.
3.2. Pe o mances o he me hod
Two es soils samples (125 g each) we e analyzed using
his me hod, whose pe o mances a e summa ized in Table
2. Mo concen a ion in he solu ions a e a below ou
uppe limi o 5–10 ppb; using his in o ma ion, i is
possible o assu e ha
99
Tc coun ing could be done in
se e al en i onmen al samples wi hou spec al in e e -
ences associa ed o concomi an Mo iso opes. I is qui e
in e es ing o see ha DF o Molybdenum inc eases
almos an o de o magni ude a e epea ing he TEVA
esin sepa a ion p ocedu e h ee imes (aliquo S32) ins ead
o wo imes (aliquo S31). This ac is in ag eemen wi h
ou p e ious s udies (Mas e al., 2004).
The chemical yields o Tc a e e y low. This is a
consequence o a combina ion o ci cums ances: (1) he
used sample masses a e g ea e han 100 g, and in his way,
possibly, he ex ac ion e ficiency du ing he acid leaching
diminishes in a e y impo an p opo ion. (2) Using 0.5 M
HNO
3
du ing he sepa a ion wi h he TEVA Spec esin
ins ead o 0.1 M HNO
3
dec eased he esin’s selec i i y o
Tc along he washing p ocess (Tagami and Uchida, 2000).
I is easy o see ha hese MDMC alues a e smalle
han hose achie ed in some o he p e iously men ioned
ou ine me hods. Howe e , ou MDMC alues a e highe
han he
99
Tc concen a ions epo ed a allou le el
(e.g., Tagami and Uchida, 2002). They p e iously p oposed
he Tc ola iliza ion om soil samples (Tagami and
Uchida, 1993), ollowed by apping in aqueous solu ions.
Using his app oach, he e ec i e concen a ion o up o
500–1000 g o soil has been done. Fu he mo e, e ec i e
emo al o many ma ix elemen s was achie ed. Un o u-
na ely we do no ha e ha kind o usion de ices a ou
labo a o y. Howe e , ou limi s o de ec ion a e in a ange
o 50–700 imes less han hose Tc concen a ions a ising
om hea ily con amina ed places, such as o es soil
samples nea o Che nobyl nuclea plan (Uchida e al.,
1999). This ac ma ks he limi capabili ies o ou me hod:
al hough we a e no ye able o de ec allou le el
echne ium, we could easily de ec se e e con amina ion
e en s, which could be di ficul o de ec using he ou ine
me hods al eady men ioned.
I is necessa y o bea in mind ha he capabili ies o his
me hod o a g ea e sample mass amoun a e limi ed by
he ac ha he only way o e ec i ely emo ing Mo
a oms is ela ed o he capabili ies o he TEVA Spec esin
(acco ding o ou p e ious esul s, i seems ha he
combina ion o p ecipi a ion+LLX does no in oduce
a e y e ec i e decon amina ion om Mo). Thus, i
necessa y, an al e na i e scheme would conside a ba ch
sepa a ion o Tc om Mo mixing he loading solu ion wi h
a la ge amoun o esin in o a ba el, and hen epea ing
he p e iously explained me hod using a home-made
column, ins ead o he comme cially a ailable mic ocol-
umns.
I can be concluded ha his me hod o e s a good
commi men be ween limi o de ec ion and in e e ing
elemen DF, a e less han 20 h eal ime analysis.
ARTICLE IN PRESS
ABCDEFG
100
80
60
40
20
3
4
5
6
0
Soil sample code
Pe cen age o 99mTc e ained in he soil (%)
Mass losses a e igni ion (%)
Fig. 1.
99m
Tc e en ion (%) and mass losses (%) a e educing o ashes
he soil samples used o check he p e ea men s ep o he me hod. Please,
no e he double scaling. &: Pe cen age o ace e ained in he soil. K:
Mass losses a e educ ion o ashes.
0.00 0.02 0.04 0.06 0.08 0.10 0.12
100
80
60
40
20
0
Mass o FeSO4⋅7H2O pe g am o solid sample (g g-1)
Pe cen age o 99mTc e ained in he supe na an (%)
Fig. 2.
99m
Tc e en ion (%) in he supe na an as a unc ion o he
educing compound (FeSO
4
7H
2
O) mass added o each es soil sample
p io o he Techne ium p ecipi a ion s ep (See he ex o de ails).
Table 2
Resul s ob ained o he di e en aliquo s o he es soil samples a e
applying he di e en me hods explained in he ex
Chemical
yield (%)
CF DF o
Mo
DF o
Ru
MDMC
(Bq kg
1
)
32.071.4 4.670.2 487 X9500 0.02
29.071.4 4.070.2 3500 X9500 0.01
J.L. Mas e al. / Applied Radia ion and Iso opes 64 (2006) 502–507 505
3.3. Valida ion o he echnique
Due o he lack o e e ence ma e ials o Tc wi h
ce ified concen a ions, alida ion o he me hod was
ca ied ou using fi e b own algae samples (McCa ney
e al., 1999a). Two eplica es we e analyzed o e e y
sample (A–E in o de o inc easing adioac i e concen a-
ion). Masses anging om 0.5 o 20 g we e used in each
analysis, depending on he expec ed concen a ion. The
a e age and unce ain y alues a e p esen ed in Table 3.
Ou esul s a e in good ag eemen wi h he consensus
alues o he in e -compa ison exe cise. Unde hese
condi ions, we can assume his me hod as alida ed o a
wide ange o echne ium concen a ions.
3.4. En i onmen al samples om he Sou h–Wes o Spain
Di e en kinds o samples aken om he Sou h o
Spain we e analyzed using his me hod. Ou hypo hesis is
ha unde ec able
99
Tc concen a ions a e expec ed, as his
iso ope would p oceed mainly om global allou . In his
way, we expec o show he eal capabili ies (and, specially,
he eal limi a ions) o his me hod. Resul s a e gi en in
Table 4.
I is easy o see ha almos all he adioac i i y
concen a ions o soils a e unde he MDMC, al hough
he CFs a e usually high. The mass ac i i y co esponding
o he DFS is ac ually equal o he MDMC, in o he
unce ain y in e als. This ac shows he ex ao dina ily
low amoun s o
99
Tc p esen in samples om egions no
di ec ly a ec ed by nuclea indus ies. The o igin o Tc in
hese kinds o samples would be ela ed o he mili a y
a mosphe ic nuclea es s du ing he second middle o 20 h
cen u y. Assuming a mean esidence ime o abou 18
mon hs (Ga cia-Leon e al., 1993), he wo king hypo hesis
would be an almos comple e e u n o Tc o he ea h
su ace. Ou esul seems o suppo such a hypo hesis. Ou
p e ious analysis o ainwa e samples aken a he same
loca ion seems o suppo his conclusion (Mas e al., 2004).
Fu he mo e, Tagami and Uchida (1996) ecen ly published
some o hese da a calcula ed om samples aken a
Hi achina a (Japan). They es ima ed Tc concen a ions in
d y allou as less han 0.4–0.9 mBq m
2
mon h
1
.Ou
esul s show an ac i i y deposi ion equal o (o lowe han)
0.06 mBq m
2
mon h
1
. And hen, e y high ag eemen
be ween he e e ed conclusions is obse ed.
Rega ding he sea g ass samples, no de ec ion o Tc was
possible. This is he expec ed esul , as acco ding o Bohn
e al. (1984), he echne ium CFs o hese species a e a
leas h ee o de s o magni ude less han o b own
seaweed. Bea ing in mind p e ious esul s o b own
seaweed collec ed om he same egion, (Manjo
´n e al.,
1995), he echne ium concen a ion in sea g ass would be
o0.1 mBq kg
1
. Hence, once again, ou esul s below
MDMC a e in ag eemen wi h ou hypo hesis, suppo ing
he lack o any s ong Tc en ance o his a ea.
4. Summa y and conclusions
Measu emen o
99
Tc by ICP-MS in en i onmen al
samples equi es decon amina ion om Mo and Ru o
a oid isoba ic o e lap and in e e ences due o ins u-
men al abundance sensi i i y. A adiochemical me hod has
been p oposed o he ea men o di e en kinds o solid
samples, which sa is ac o ily decon amina es he sample
om Mo and Ru. I couples high sample concen a ion
using a cop ecipi a ion-LLX s ep wi h u he solu ion
pu ifica ion achie ed by anion exchange ch oma og aphy.
A e y in e es ing poin has been ound, as epea ing he
sepa a ion wi h a TEVA Spec
TM
esin g ea ly imp o es
he sepa a ion om Mo a oms p esen in he sample; hus,
he sensi i i y o he me hod is imp o ed. This e ec is
achie ed in a less ime consuming way han dilu ing (o
e en e apo a ing o d yness) he leaching solu ion.
The g ea e pa o Tc concen a ions ound seems o lie
unde he limi s o de ec ion (which is in he ange o
se e al en hs o mBq kg
1
), as expec ed bea ing in mind
ha all he samples we e aken om a egion a om any
nuclea indus y.
Acknowledgemen s
The au ho s would like o exp ess hei deep acknowl-
edgemen o he s a a Cen al Resea ch Se ices
(Uni e si y o Huel a) and Radiological P o ec ion
ARTICLE IN PRESS
Table 3
Consensus alues ob ained o fi e b own algae samples in an
in e compa ison exe cise, and he esul s we ound when applying he
S3 me hod
Sample Consensus alue (Bq kg
1
) This wo k (Bq kg
1
)
A 5.971.1 4.670.3
B 58.374.6 48.871.0
C (3.9170.13) 10
3
(3.2970.14) 10
3
D (1.79170.078) 10
4
(1.61470.055) 10
4
E (1.3370.12) 10
5
(1.1870.03) 10
5
Table 4
Ob ained esul s o
99
Tc in a d y allou sample (DFS), wo Seag ass
(Zos e a Ma ina) samples (ZM1 and ZM2) and ou Medi e anean o es
soil samples (1SD1, 1SD4, 2S1 and 2S2) collec ed in he Sou h–Wes o
Spain
Sample Mass
amoun (g)
CF MDMC
(mBq kg
1
)
99
Tc
(mBq kg
1
)
DFS 125 4.470.1 16 1975
ZM1 35 1.0470.03 70 66719
ZM2 35 0.8470.03 77 60728
1SD1 125 3.6570.06 21 —
1SD4 125 4.3570.04 36 —
2S1 75 3.3770.06 32 779
2S2 90 3.7670.16 30 15726
J.L. Mas e al. / Applied Radia ion and Iso opes 64 (2006) 502–507506

Se ices, (Hospi al Juan Ramo
´n Jime
´nez, Huel a) o
hei help wi h he ICP-MS and he ace , espec i ely.
Special acknowledgemen s mus be exp essed o D . Keiko
Tagami (NIRS, Chiba, Japan), D . Vale ie Oli e (SURRC,
Sco land) and D . Joaquin Gomez-Camacho (Dp o.
FAMN, Uni . Se ille, Spain) o hei kind commen s
and sugges ions and he supply o aluable samples. One o
he au ho s (JLM) g a e ully acknowledges he financial
suppo o he Scien ific Technology Agency o Japan o a
scien ific isi o he NIRS a Chiba, and is also e y
g a e ul o all he s a o his ins i u e o hei help and
wa m hospi ali y.
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ARTICLE IN PRESS
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